Application of Coulometric FFT Cyclic Voltammetry for Determination of Cholesterol Based on Cholesterol Oxidase Nano-Biosensor

In this work, a new electrochemical system was developed for determination of cholesterol based on coulometric fast Fourier transformation cyclic voltammetry (CFFTCV) in a flow injection analysis system. In this detection method, also a new cholesterol oxidase biosensor was designed by immobilizing the enzyme into a cross-linked matrix of chitosan– room-temperature ionic liquid (1-butyl-3-methylimidazolium tetra fluoroborate). Initially, the surface of a glassy carbon electrode was modified with CeO2 NPs and then by the electrodeposition of Au particles onto the thiol functionalized multiwalled carbon nanotubes. Scanning electron microscopy and impedance spectroscopy was use to characterize the biosensor. The presence of Au and CeO2 nanoparticles in the matrix of provides an environment for the enhanced electrocatalytic activities. Under optimal conditions, the biosensor exhibited a linear response to cholesterol in the concentration range of 0.01–10 ?M with a correlation coefficient of 0.99, good sensitivity, a low response time, repeatability (R.S.D value of 1.9%) and long term stability, 45 days with a decrease of 4% response